Ćurić, MandaBabić, DarkoVišnjevac, AleksandarMolčanov, KrešimirSimple Route to the Doubly <i>o</i><i>rtho</i>-Palladated Azobenzenes: Building
Blocks for Organometallic Polymers and MetallomesogensA new class of doubly cyclopalladated complexes, {PdCl(dmf)}<sub>2</sub>(μ-azb) (<b>1</b>) and {PdCl(dmf)}<sub>2</sub>(μ-aazb) (<b>2</b>), has been prepared in
dimethylformamide (dmf) by reaction of azobenzene (azb) and
4-aminoazobenzene (aazb), respectively, with an excess of
PdCl<sub>2</sub>(CH<sub>3</sub>CN)<sub>2</sub> complex. Recrystallization of <b>1</b> and <b>2</b> in dimethyl
sulfoxide (dmso) yields complexes {PdCl(dmso)}<sub>2</sub>(μ-azb) (<b>3</b>) and
{PdCl(dmso)}<sub>2</sub>(μ-aazb) (<b>4</b>), respectively. The crystal structures of
<b>1</b> and <b>4</b> have been determined by X-ray diffraction. All complexes
are characterized by <sup>1</sup>H and <sup>13</sup>C NMR spectra and elemental
analysis. In both crystal structures, solvent molecules are bound
to palladium through oxygen atoms and oriented trans to carbon.
In view of greater preference of palladium to nitrogen and sulfur
atoms, the experimental structures were rationalized by quantum-chemical calculations and confirmed as the most stable isomers.aazb;crystal structures;complex;13 C NMR spectra;palladium;azb;CH 3 CN;PdCl2005-08-22